1. Field of the Invention
The present invention relates to a motor control apparatus, and more particularly to a motor control apparatus suitable for controlling an AC motor by using a current sensor.
2. Description of the Related Art
Hybrid vehicles and electric vehicles, which have an electric motor for their drive unit, are recently highlighted as environmentally-friendly automobiles. Some hybrid vehicles are already commercialized. In general, hybrid vehicles have a wheel-drive AC motor whose drive is controlled by an inverter. It is demanded that the AC motor responsively generate a desired torque, which changes in accordance with a driver's request. A current sensor for detecting an AC current supplied to the motor is used when the inverter controls the AC motor.
As for the AC motor mounted in a hybrid vehicle, therefore, a current value measured by a current sensor is basically used to control the inverter. At least two current sensors are required.
In consideration for a current sensor failure, however, the invention disclosed, for instance, in JP-A-2005-160136 uses a total of four current sensors (two current sensors per phase) and compares the outputs from the individual phase current sensors to check for a current sensor abnormality.